Research and Application of Low Cost and Efficient CBM Drilling Technology in South Yanchuan

Low reservoir volume and low single well production are bottlenecks that restrict coal bed methane(CBM) development, so how to improve the drilling efficiency and how to control the costs are the keys to the effective development of CBM. After summarizing the previous drilling experiences in South Yanchuan CBM block, the well factory drilling model was successfully applied and many technical research and field applications focused on reducing the cost and increasing benefits were carried out. Techniques included cluster well optimization, preventive deviation anticollision, navigational BHA, individualized bit design, efficient leak stoppage, etc. Then, the learning curve was used to optimize and improve key technologies and develop low cost and efficient drilling technology. Low cost and efficient drilling technology that was developed in the South Yanchuan CBM Block was applied to 808 wells and the operations were performed with good quality and high efficiency, in which the average single well drilling cycle was shortened by more than 30.3%, and productivity construction and penetration rate were improved by over 51.6%. The application showed that the well factory drilling mode could be employed in the field of CBM development to significantly control drilling costs, improve the efficiency to cost-effectively develop CBM.